Vaporization systems are used in decontamination systems to produce gases such as vaporized hydrogen peroxide. As used herein, the term “decontamination” refers to processes, including, but not limited to, “deactivation of biocontamination,” “deactivation of chemical contamination,” “sterilization,” “disinfection” and “sanitization.” In the case of a typical hydrogen peroxide decontamination system, an aqueous solution of hydrogen peroxide is delivered to a vaporizer where the aqueous solution of hydrogen peroxide is vaporized. The resulting mixture of vaporized hydrogen peroxide and water vapor is then injected into a treatment chamber, where articles are decontaminated by exposure to the vaporized hydrogen peroxide.
Efficient vaporization of the aqueous solution of hydrogen peroxide is important to the effective operation of a decontamination system using vaporized hydrogen peroxide. The aqueous solution of hydrogen peroxide is typically comprised of liquid hydrogen peroxide diluted with water. When solutions are vaporized, a disproportionate amount of the more volatile component will vaporize first. In the case of the abovementioned aqueous solution of hydrogen peroxide, water is more volatile than hydrogen peroxide and therefore vaporizes more quickly than the liquid hydrogen peroxide. Thus, the water vapor reaches the articles in the treatment chamber to be decontaminated before the hydrogen peroxide vapor, and in higher concentrations. Consequently, the water vapor becomes an effective barrier to hydrogen peroxide penetration around small crevices and lumens of the articles in the treatment chamber.
In view of the aforementioned problem, decontamination systems have been developed that vaporize an aqueous solution of hydrogen peroxide by injecting the aqueous solution of hydrogen peroxide into a vaporization chamber, wherein successive increments of the aqueous solution of hydrogen peroxide are metered onto a heated surface inside the vaporization chamber. Each increment of the aqueous solution of hydrogen peroxide is substantially instantaneously vaporized before the next succeeding increment of the aqueous solution hydrogen peroxide is metered onto the heated surface.
One problem with such systems is that over time the concentration of vaporized hydrogen peroxide within the system may not reach desired levels because the efficiency level of the vaporizer may have decreased. Efficient vaporization of an aqueous solution of hydrogen peroxide depends upon substantially instantaneous vaporization of an increment of the aqueous solution of hydrogen peroxide. When an increment of the aqueous solution of hydrogen peroxide does not substantially instantaneously vaporize, the efficiency of the vaporizer decreases. Such a decrease in efficiency may occur because deposits develop on surfaces that contact and transmit heat to the aqueous solution of hydrogen peroxide. The decreased efficiency will result in lower than desired concentrations of vaporized hydrogen peroxide within the decontamination system. A reduction in the concentration of vaporized hydrogen peroxide within the system may result in reduced efficacy of decontamination or increased decontamination times.
The present invention provides an apparatus and a method for determining the efficiency of a vaporizer in a decontamination system.